Copahue, Chile / Argentina . twenty-six (26) seismic events .

Tue, Mar, 8, 16
Posted by : Georges VITTON

The level of activity of the volcano is at: YELLOW level, changes in the behavior of volcanic activity – probable time for an eruption : weeks / months.

Based on the analysis of information obtained by monitoring equipment and monitoring of the volcano, the Servicio Nacional de Geologia y Mineria (SERNAGEOMIN) – Volcanológico Observatorio de Los Andes del Sur (OVDAS) announces:
During this period, twenty-six (26) seismic events including nine (9) who were classified as volcano tectonic (VT) associated with rock fracturing processes were recorded.
Similarly, seventeen events (17) associated with the fluid dynamics within the volcanic edifice, which fourteen (14) were identified as long-period earthquakes (LP) and three (3) as very long period events (VLP) were recorded.
As for the VT type of seismicity, their local magnitude (ML) were lower, on the order of M 1.7 , with locations widely dispersed . The higher energy event was located on the North-East side (ENE) at 10 km of the crater El Agrio with a depth of about 7 km.

In connection with the LP-type events, they have a reduced displacement values (DRC) under 1.5cm2. Seismicity of VLP types presented lower displacement values (DRC) of 7.0cm2, mainly located around the active crater with epicentral distances of less than 3.5 km.
During the month, there was a constant tremor signal, mainly associated with particulate emissions (gases and ash) from the crater El Agrio, which recorded DRC values with a rising trend, with values calculated below 5cm2, values considered as intermediate for this volcano.

The dominant frequencies are concentrated in a bandwidth between 1.0 and 2.0 Hz.
IP cameras installed near the volcano recorded the constant emission of material from the active crater (El Agrio), accompanied by incandescence.
These emissions were characterized mostly by a gray color, showing the presence of particulate matter.
The maximum height measured during this period was 1,250 m above the active crater (El Agrio).

With satellite images, the distance reached by the ash cloud was observed up to 100 km from the El Agrio crater with directions preferentially to the southeast and east.
From the data obtained from three (3) GNSS stations that monitor the deformation of the surface of the volcano, it is observed that movements in both horizontal and vertical are minimal, the speed calculation is close to zero.

The sulfur dioxide emission (SO2) recorded on the Copahue volcano by the team DOAS (Differential Optical Absorption Spectrometry), Triplets Station, located 5 km east-northeast of the active crater, presented a monthly average value of 1,125 ± 176 t / day and a maximum value observed during the second fortnight of 4264 t / day, registered on 25 February.
The average flow is considered at normal levels for this volcano.

Images published by the Group Sulphur dioxide (instrument to monitor ozone – http://so2.gsfc.nasa.gov/) and NESDIS (National Environmental Satellite, Data and information – IMO Group http: // satepsanone.nesdis .noaa.gov) show no significant changes in the volcano area for SO2 emissions in the atmosphere.
Thermal radiation released by the MODVOLC (Moderate Resolution Imaging Spectroradiometer) MODIS on its website (http://modis.higp.hawaii.edu/) and Mirova (Middle InfraRed Observation of volcanic activity) on its website (http : / /www.mirovaweb.it/), surveillance systems that indicate significant changes in surface temperature, shows no thermal warning reported in the area associated with the volcano.

According to the monitoring indicators described above , it follows that the activity related to the interaction of a magma body of small volume and the hydrothermal system continue, without unbalancing the system.
This activity may continue for a long period of oscillating manner, without excluding specific increases related to small phreatic explosions and / or low strombolian activity. Therefore, it is considered that, immediately next to the emission center , there is a high risk area and therefore an access restriction is recommended, within 1.5 km around the crater El Agrio, and maintaining the level of technical alert at level Yellow .